Control of intragastric acidity with over‐the‐counter doses of ranitidine or famotidine

Abstract

Background: Histamine H2‐receptor antagonists are available over the counter for the treatment of heartburn. Aim: To compare the effects of low doses of ranitidine and famotidine on intragastric acidity in a three‐way crossover study. Methods: Healthy subjects (12 male, 12 female) were dosed on three occasions with single oral doses of placebo, ranitidine, 75 mg, and famotidine, 10 mg, 1 h after lunch. The pH of gastric aspirates was then measured for 20 h. Subjects ate standard meals and snacks. Analysis of variance was used to determine the statistical significance of differences in acidity (mmol/L) during the day (12.30–22.30 hours) and night (22.30–08.30 hours). Results: Ranitidine and famotidine were superior (P < 0.05) to placebo in decreasing acidity for daytime and night‐time intervals. There were no significant differences in mean gastric acidity between ranitidine and famotidine during the daytime (11.37 mmol/L vs. 13.42 mmol/L, respectively) and night‐time (23.57 mmol/L vs. 24.74 mmol/L, respectively). Intragastric acidity after ranitidine was significantly lower than that after famotidine in the first 2.5‐h period following dosing (4.32 mmol/L vs. 9.28 mmol/L; P < 0.05). Conclusions: Lunchtime doses of ranitidine and famotidine decreased acidity during day‐ and night‐time periods. The effect of ranitidine was significantly greater for the first 2.5 h after dosing.

Extremely Early Onset of Ranitidine Action on Human Histamine H₂ Receptors Expressed in HEK293 Cells

“…In line with this, it is important to determine which particular H 2 R antagonist has the earliest onset of H 2 R inhibition in humans. Several studies using human subjects have shown that ranitidine is more prompt than famotidine in controlling gastric acidity [13, 14, 17]. In the present study, we found direct evidence that ranitidine interacts with the human H 2 R much more rapidly than does famotidine.…”

“…Several reports have focused on gastric acidity effects in human subjects of the most widely used marked H 2 R antagonists: ranitidine and famotidine [13, 14, 15, 16, 17, 18]. Accumulating clinical data suggest that ranitidine has an earlier onset of action than famotidine, whether administered orally or intravenously [13, 14, 17].…”

“…Accumulating clinical data suggest that ranitidine has an earlier onset of action than famotidine, whether administered orally or intravenously [13, 14, 17]. Our aim herein was to analyze directly the onsets of famotidine and ranitidine interactions with human H 2 Rs.…”

In vitro effects of famotidine and ranitidine on lower esophageal sphincter tone in rats

“…One of the commonly used medical agents has been H 2 receptor antagonists; however, PPI s have recently become superior to H 2 receptor antagonists in treating esophageal mucosal injury and erosive esophagitis due to GERD (31)(32)(33)(34). Despite an adequate treatment regimen, the patient population who are poor or non-responders to PPI treatment will constitute 10-30% of all GERD patients.…”

Low‐dose ranitidine for the relief of heartburn

“…The H 2 ‐receptor antagonist, ranitidine, inhibits gastric acid and fluid secretion in both basal and stimulated states, thereby increasing the pH and decreasing the volume of gastric contents available for reflux into the oesophagus 5 . The usual prescription doses of ranitidine are effective in relieving heartburn 6 and pharmacodynamic data indicate that lower doses of ranitidine may also be effective for the treatment of episodic heartburn 7 –9 …”